Process of tanning leather.



UNITED STATES JAMES C. CLEARY, OF CHICAGO,

PATENT OFFICE.

ILLINOIS.

PROCESS OF TANNING LEATHER.

No Drawing.

To all ur/win 1' t may concern Be it known that 1, JAMES C. CLEARY, a citizen of the United States, and a resident of Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Processes of Tannin; Leather, of which the following is a specification.

This invention relates to a process of tan ning hides and relates particularly to a process of tanning hides with liquor produced by the destructive distillation of lignite of the cretaceous age or period, as fully set forth and described in an application for l S. Letters Patent heretofore filed by George Kimball on the out day of April, 1908, Serial Number 428,939, as well as in the later application filed by said Kimball on the 30th of June, 1913, Serial No. 776,640.

The process set forth in the aforesaid applications is briefly as follo\\'s:,-1he hides to be tanned are first pickled, in substantially the usual way, and are then immersed until properly tanned in a bath consisting of a liquor such as is obtained by the destructive distillation of a lig'nite coal of the eretaccous age. or period which occurs and is produeed in several counties in the State of Arkansas, including the county of ()uachita in said State and described on page 28 of a work known as The Minerals and lfoc/rs of Arkansas, published by 1*. L. llarvey, B. S. in 1886. For purposes of convenient reference. the particular lignite from which the tanning liquor is obtained for use in practisin; the process ol the aforesaid application will be referred to hereinafter as ()uachita lifl'lllit. 'lhis tanning liquor is obtained by the destructive distillation of the lignite for a period of from seven to ten hours at temperatures of from 300 to 450 F., the distillation being perfm'med in any usual form of retort. The distillate consists principally of two distinct products. a watery liquor and an oil, which separate by gravity, the watery liquor being the heavier and soon settling when the full liquor is allowed to stand, so that it can be readily drawn off from the oil. The watery distillate carries in'solution certain of the higher phenols, and this watery distillate alone may be used or the full liquor, containing the oil, may be used, the oily distillate operating" to impart a dark color and a distinctive odor to the leather.

Specification of Letters Patent.

Patented Aug. 18, 1914.

Application filed October 30. 1911. Serial No. 657,644.

It has been found that, in practising the process set forth in the aforesaid application, the leather produced thereby is too porous for ordinary uses, making it necessary that it be sinjected to special treat- -ment to impart the desired density and firmness thereto. On the other hand, it is well known by persons skilled in the tanning art that hides tanned by means of usual tanning agents, such as extract of hemlock, oak, quebracho, alum, chromium, and the like are hard and brittle and break very easily, it' bent, making it necessary to treat them with grease to render the leather soft and pliable.

I have discovered that by using as a tannine agent a mixture of the aforesaid liquor distilled from Ouachita cretaceous lignite and one of the Well known tanning and for some hides, particularly sheepskins, a mixture of Ouachita cretaceous lignite distillate and a mineral tanning agent, as alum, chromium, or an equivalent thereof, a leather will be produced having the density and firmness of leather tanned with usual vegetable or mineral tannages now in common use, and the softness and pliability of leather tanned with the ()uachita cretaceous lignite distillate, and that the tanning process requires only from one quarter (1) to onethird (4,) of the time required for tanning similar hides by present processes. For example, it requires from three to four months to tan sole leather. harness leather and the like by present methods, whereas, by my improved process leather ot the same character and believed to be of superior quality can be produced in from four to tire weeks.

In the practice of my invention, the hides are first pickled, substantially in the usual way, and are then immersed in a bath consisting of amixture of liquor produced by the destrru-tive distillation of Ouachita cretaceous lignite and a usual tanning, agent, preferably one'which contains tannic acid, as extract of hemlock, oak. quebracho. For most purposes, I prefer to mix said tannages in the proportions of about eleven (11) pounds of said extract to forty (40) gallons of the liquor distilled from Ouachita cretaceous lignite. Also. I find that the best results are obtained by adding the extra(rt-hemlock. oak or the like-grad ually, increasing the proportion and effect a gents, as hemlock extract or its equivalent,-

and of Ouachita lignite distillate speci-' fied, as excellent results may be obtained by varying the proportions thereof Within a considerable range.

The length of time required for tanning different hides Will vary, but skilled operators can readily ascertain by examination When the hides are thoroughly tanned.

lVhen the tanning process is completed, the hides are removed from the liquor and subjected to any desired finishing process.

I claim:

1. The process of tanning hides Which consists in first preparing the hides in any usual manner, and in then soaking them in a bath consisting of liquor such as is produced by the destructive distillation of Ouachita cretaceous lignite and a usual tanning extract or agent, substantially as described.

2. The process of tanning hides Which consists in first preparing the hides in any usual manner, and in then soaking them in a bath consisting of liquor such as is produced by the destructive distillation of Ouachita cretaceous lignite and a usual tanning extract or agent in substantially the proportions of forty (40) gallons of Ouachita distillate to eleven (11) pounds of extract, substantially as described.

3. The process of tanning hides which consists in first preparing the hides in any usual manner, and in then soaking them in a bath consisting of liquor such as is produced by the destructive distillation of Ouachita cretaceous lignite and a usual tanning extract or agent, the extract being added gradually as the tanning process progresses, substantially as described.

4:. The process of tanning hides which consists in first pickling the hides in the usual manner, then soaking them in a bath consisting of liquor such as is produced by the destructive distillation of Ouaohita cretaceous lignite to which a tanning ex tract is added in about the proportion of forty gallons of such distillate to one pound of extract, and then adding to such bath about three pounds of extract at the beginning'of the second Week, three pounds at the beginning of the third Week, and four pounds at the beginning of the fourth Week, the soaking continuing until about the end of the fourthWeek.

In testimony, that I claim the foregoing as my invention, ll aflix my signature in presence of two subscribing Witnesses this. 17th day of October, A. D. 1911.

JAMES C. GLEARY. "Witnesses:

GERTRUDE FALING, E. M. KLATGHER. 

